Detailed Magnetic Equivalent Circuit Based Real-Time Nonlinear Power Transformer Model on FPGA for Electromagnetic Transient Studies

A detailed power transformer electromagnetic transient model would help in accurately predicting transient stresses and formulating adequate protection strategies in power systems. This paper presents a real-time nonlinear high-resolution magnetic equivalent circuit (HR-MEC) based transformer model on the field-programmable gate array for hardware-in-the-loop simulation. This model is inspired by the mesh generated in finite-element method (FEM) tools to depict the major flux paths in the transformer. All of the major nonlinear phenomena such as saturation, hysteresis, and eddy currents are captured in the transformer hardware emulation whose modules were developed in a 32-b floating point precision VHDL. The developed HR-MEC model and nonlinear numerical solution have been fully parallelized in hardware to achieve the lowest latency in the real-time implementation. The hysteresis in the transformer core is modeled using Preisach theory, and eddy currents are incorporated using a frequency-dependent network. The real-time results are validated using 3-D FEM analysis in JMAG software.